Comment 19 for bug 1003185

I was attempting to replicate the bug so that I could see whether installing gnome and gnome-shell would fix it for me. I cannot replicate it any more. This might be the fix: this morning I installed the new kernel from the Ubuntu repos.
$ uname -r
3.5.0-23-generic

@Aaron: I didn't read the whole page that you linked, but the latest comment suggests that that bug may have been fixed with this same kernel
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1101666/comments/55